Rhubarb-Strawberry Crumble

This is based on a recipe from The Gourmet Cookbook, the first edition (2004) of which I scored on Amazon for $12 because of some kind of production error that made the headings unreadable for people with certain kinds of vision impairments. I hope I never develop that impairment as I age. I adore this cookbook.

Filling:
2 lbs. strawberries, hulled and halved
1 lb. rhubarb, sliced 1/2-inch thick chunks
1 c. sugar
3 T. cornstarch
1 T. lime juice
1/8 tsp. salt

Topping:
1 1/4 c. rolled oats
3/4 c. flour
3/4 c. brown sugar, packed
1/4 tsp. salt
12 T. unsalted butter, cut into cubes

Preheat the oven to 425 F. Stir the filling ingredients in a large bowl and then pour into a 13-inch baking dish. (I use my lasagna pan.) Stir all the topping ingredients, except the butter in another bowl and then crumble in the butter with your fingers. Spread it evenly over the top, bake for 45-50 minutes until the topping is nicely browned and the fruit is bubbling. Serve warm or at room temperature.